What causes Scout to question "pulpit Gospel"? How does her questioning relate to Miss Maudie?

From the text:

Apparently deciding that it was easier to define primitive baptistry than closed communion, Miss Maudie said: "Foot-washers believe anything that’s pleasure is a sin. Did you know some of ‘em came out of the woods one Saturday and passed by this place and told me me and my flowers were going to hell?"

 "Your flowers, too?"

 "Yes ma’am. They’d burn right with me. They thought I spent too much time in God’s outdoors and not enough time inside the house reading the Bible."

 My confidence in pulpit Gospel lessened at the vision of Miss Maudie stewing forever in various Protestant hells. True enough, she had an acid tongue in her head, and she did not go about the neighborhood doing good, as did Miss Stephanie Crawford. But while no one with a grain of sense trusted Miss Stephanie, Jem and I had considerable faith in Miss Maudie. She had never told on us, had never played cat-and-mouse with us, she was not at all interested in our private lives. She was our friend. How so reasonable a creature could live in peril of everlasting torment was incomprehensible.

In Chapter Five, Scout asks Miss. Maudie about Boo Radley, and Miss Maudie says that he's still alive, he just doesn't like to come outside. She also says that most of the rumors about him aren't true. Miss Maudie explains that the Radleys are foot-washing Baptists - they believe all pleasure is a sin against God, and stay inside most of the time reading the Bible. She says that Arthur was a nice boy when she used to know him.